Undergrad Observing a Collapsing Shell: Time Dilation Explained

[blademan9999]

TL;DR

Observer inside collapsing shell problem.

What does and observer inside of a collapsing shell observe? Lets say we have a shell of matter collapsing to a black hole. What would observers near the center see? How would the rest of the universe appear when,

The shell is approaching the Schwarzschild radius?

After the shell passes the Schwarzschild radius?

Time Dilation inside a hollow shell According to here you get time dialation, so what happens as the shell contracts?

Say the observer has a clock, and the inside of the shell is like a mirror, there's a clock attached to the shell and finally there's a clock at a great distance. How fast would these clocks go relative to eachother?

Until the shell reaches the observer, the observer is free to move aorund, so the issue to me seems to be that whe have a shell observer inside of a black hole, which normally you're not supposed to be able to have.

 

[berkeman]

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[Ibix]

See https://www.physicsforums.com/threa...of-a-singularity-before-it-is-formed.1017274/. A lot of your question is answered by that. Basically, the event horizon forms inside the shell and expands outward at the speed of light. Once it passes you (you can't detect anything locally as it does) you're doomed. You just don't see any local curvature until the shell passes you in the other direction.